The Steelers placed an original-round tender of $1.323 million on Sanders, who is a restricted free agent. The team will be able to match any offer sheet he may sign or receive a third-round draft pick as compensation.

The cash-strapped Steelers are already thin at wide receiver and may not be able to match a higher offer for Sanders while remaining under the salary cap. Sanders, who turns 26 on Sunday, is expected to be the Steelers' No. 2 wide receiver this season after Mike Wallace signed a five-year deal worth $60 million with the Miami Dolphins.

On Thursday, the Steelers lost a pair of defensive backs to free agency.

Keenan Lewis, the team's No. 2 cornerback last season, signed a five-year deal to join his hometown New Orleans Saints.

"(I) am thankful for the time I spent with the Pittsburgh Steelers and wish them continued success," Lewis, 26, said in a statement released by the Saints.

Meanwhile, backup safety Ryan Mundy reached a deal with the New York Giants. Mundy, 28, started three games for the Steelers last season but played his way out of the starting lineup and was replaced by Will Allen.

A Dormont native and Seton-La Salle High School graduate, Gradkowski most recently played with the Cincinnati Bengals. He's also played for the Buccaneers, Browns and Raiders during his seven-year NFL career. His brother, Gino, is an offensive lineman with the Baltimore Ravens.

Colon's departure had been anticipated after the team signed offensive lineman Ramon Foster to a three-year deal on Monday. Colon, 29, was designated as a June 1 release, which allows him to become an unrestricted free agent and sign with another team. It also clears $5.5 million in salary cap space for the Steelers, but only after June 1.